BIOL 111 Lecture Notes - Fossil Fuel, Nitrogen Fixation, Millennium Ecosystem Assessment

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Global Change
Rates of change in ecosystems has increased dramatically since industrial revolution
Anthropocene: Current period in Earth’s history characterized by the large changes
human have had on ecosystem on a the global scale
Global Change: planetary scale changes in biophysical and socio-economical
processed altering structure and function of Earth
Ecosystem services:
1. provide services (food, water, flood control, coil stabilization, climate
regulation, carbon fixation)
2. reducing famine and disease and poverty
3. financial benefits, w/o a healthy ecosystem economy can’t flourish
Millennium ecosystem assessment:
-Started by UN in 2001 to track our ecosystem changes, reviewed by experts
and prepared globally, assessing globally and regionally
- Substantial and irreversible ecosystem losses over 50 years (ex. Land to
crop land in 30 years than in the past 150 years, 20% of coral reefs lost and
20% degraded in past several decades, 35% mangroves lost, water in
reservoirs x4 since 1960, withdrawals from rivers and lakes x2 since 1960)
Main forms of global change:
1. Habitat change:
a. Over last century most severe in tropical forest, temperate grassland,
inland water, coastal
b. Tropical forest: most diversity, landcover has declined 90% = ½
species lost 1 million species projected to be lost by the end of the
21st century
i. The greater the patch size the less effect the edge habitat
changes will have, as patch decreases a greater proportion is
on the undesirable edge
ii. Isolated patches lose species more quickly than connected
iii. Lungs of the earth?: cover 3% of earth surface, have highest
average net primary production, but are not as important as
oceans cause oceans are bigger
2. Climate change:
a. Had greatest impact on polar regions
i. Mean warming in 2007 since 1950-1980 is significantly higher
in polar regions than at equator
ii. Albedo: snow and ice have high reflection potential, ice and
snow melted with global warming = lowering of albedo and
therefore warm more melting more ice and snow
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